There are a variety of applications in which it is desirable to supply a flow of liquid to a turbine to cause it to rotate, thereby to generate mechanical and/or electrical power. There are also many cases in which the flow of liquid naturally available is not always equal to that which it is desired to have available for driving the turbine. For example, the rate of flow from the source may be at a highly variable rate, sometimes being below the optimum flow rate and other times being well in excess of the maximum desired flow rate; currents flowing at a very high per rate can readily produce undesired back-up of the liquid in the conduit supplying the turbine.
As an example, in U.S. Pat. No. 4,352,024 of Harry D. Troyen, entitled System for Generation of Electrical Power and issued Sept. 28, 1982, there is shown a system for generating electrical power from the flow of waste liquid, and a special arrangement is shown for operating one or more valves to bypass a substantial part of the liquid flow when it occurs at too high a rate, so as to avoid excessive flow through the turbine and excessive backup of the liquid in the supply line. While such valving arrangements can operate successfully, they do require special relatively expensive apparatus involving a number of moving parts.
Accordingly, it is an object of the present invention to provide apparatus for controlling the flow of liquid to a turbine, which apparatus does not require any moving parts.
Another object is to provide such apparatus which is inexpensive and extremely reliable.